1. Field of the Invention
The present invention relates to liquid crystal display devices. In particular, the present invention relates to liquid crystal display devices having a touch panel function.
2. Description of the Related Art
A touch panel functions as a position input device that can detect a position indicated with a finger, a stylus, or the like to generate a signal including the positional information. A capacitive touch panel can obtain positional information without being influenced by external light, unlike an optical touch panel such as an infrared touch panel. Furthermore, the capacitive touch panel can obtain the positional information at high speed as compared with a resistive touch panel and does not cause physical wear of electrodes. For these reasons, capacitive touch panels have come into wide use in the market in recent years.
In addition, as the kinds of liquid crystal display devices including a touch panel, there are an in-cell liquid crystal display device in which part of a touch panel function is provided inside a liquid crystal panel and an on-cell liquid crystal display device in which a touch panel is provided between a polarizing plate and a liquid crystal panel. The in-cell type is more advantageous than the on-cell type in manufacturing a thin and lightweight liquid crystal display device including a touch panel.
Patent Document 1 discloses an in-cell liquid crystal display device including a capacitive touch panel.